江苏省植被NPP时空特征及气候因素的影响

利用2000—2006年的EOS/MODIS卫星遥感资料,对江苏省植被净初级生产力（NPP）时空特征及气候变化对其影响进行分析。在ArcGIS软件中,建立线性回归方程获得NPP的变化斜率,分析7 a间各像元NPP的空间变化趋势。计算各像元的NPP数值与气候要素的线性相关系数,为定量阐述气候变化对植被生长的影响提供依据。结果表明,江苏省植被NPP 7 a平均值为506.6 g.m-2.a-1（以C计）,比全国同期NPP数值高出约40%。NPP表现出明显的年际变化,2004年植被年均NPP最大为530.6 g.m-2.a-1（以C计）,2000年最小,为481.1 g.m-2.a-1（以C计）。空间分布上NPP表现为东南高于西北,沿海高于内陆。2000—2006年江苏省有76%的区域植被NPP表现为显著增加,仅江苏南部少数区域表现出减少的趋势。除苏南少数区域外,气候因素控制着NPP的时空变化规律。其中气温的升高和太阳辐射的增加促进NPP提高,而降水量的增加引起NPP的降低。

Spatio-temporal characteristics of vegetation net primary productivity and climate change effects in Jiangsu province

Using MOD17A3 data from EOS/MODIS,this article analyzed spatio-temporal characteristics of vegetation net primary productivity（NPP） and effects of climate change on them in the Jiangsu province with the help of ArcGIS software.Results showed that the average value of the annual NPP（C 506.6 g·m-2·a-1） in the study area was higher than that of the whole nation during the period of 2000-2006.And an evident inter-annual fluctuation of NPP values was observed.NPP in 2004 had the largest mean value（C 530.6 g·m-2·a-1）,while 2000 had the lowest one（C 481.1 g·m-2·a-1）.With respect to spatial distribution,NPP values in the southeast parts of the Jiangsu province were higher than that of the northwest parts.Linear regression model was adopted in order to eliminate the extreme values and to investigate the changing trend of NPP values.The results demonstrated that annual NPP values in the north and centre of the study region mainly showed a tendency of increasing,while the ones in minority regions with a decreasing trend,such as the south part of the Jiangsu province.According to pixel-based correlation analysis between NPP and climate factors,vegetation NPP in most areas of Jiangsu province was sensitive to climate change except for minor regions in the south of Jiangsu.The results also revealed that while precipitation had negative and significant effects on NPP,temperature and sunshine duration time posed positive and significant effects on it.